Shinohara Naoya, Owada Takashi, Matsumoto Chieko, Uchida Shigeharu, Nagai Tadashi, Satake Masahiro, Tadokoro Kenji
Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society, Tokyo, Japan.
Trans R Soc Trop Med Hyg. 2017 Sep 1;111(9):393-401. doi: 10.1093/trstmh/trx071.
Most of the Japanese population is seropositive for anti-Japanese encephalitis virus (JEV) antibodies because of previous JEV vaccination or natural infection. Because the virological characteristics of JEV are similar to those of West Nile virus (WNV) and dengue virus (DENV), we hypothesized that anti-JEV antibodies can cross-react with WNV and DENV antigens, leading to protection against infection by these viruses.
Using isolated intravenous immunoglobulin (IVIG) from plasma collected in Japan, neutralizing activities against WNV and DENV and antibody-dependent enhancement (ADE) of these viral infections were evaluated using an in vitro assay to determine the potency of immunity against these viruses.
The prepared IVIG showed considerable neutralizing activity of 2.57 log10 reduction factor against WNV infection but showed little effect against DENV infection. A strong correlation was observed between the neutralizing activity of individual plasma samples against JEV and WNV (ρ=0.768). Moreover, IVIG showed no significant ADE of WNV infection.
Based on these results, we presume that the Japanese population is generally protected from WNV infection. Furthermore, IVIG prepared from plasma donations from Japanese individuals is expected to be an effective therapeutic agent based on its neutralizing activity against JEV and WNV.
由于既往接种过日本脑炎病毒（JEV）疫苗或自然感染，大多数日本人群抗JEV抗体呈血清阳性。由于JEV的病毒学特征与西尼罗河病毒（WNV）和登革病毒（DENV）相似，我们推测抗JEV抗体可与WNV和DENV抗原发生交叉反应，从而预防这些病毒的感染。
使用从日本采集的血浆中分离出的静脉注射免疫球蛋白（IVIG），通过体外试验评估其对WNV和DENV的中和活性以及这些病毒感染的抗体依赖性增强（ADE），以确定对这些病毒的免疫效力。
制备的IVIG对WNV感染显示出相当大的中和活性，降低因子为2.57 log10，但对DENV感染几乎没有影响。观察到个体血浆样本对JEV和WNV的中和活性之间存在很强的相关性（ρ=0.768）。此外，IVIG对WNV感染未显示出明显的ADE。
基于这些结果，我们推测日本人群总体上对WNV感染具有抵抗力。此外，由日本个体捐赠的血浆制备的IVIG因其对JEV和WNV的中和活性，有望成为一种有效的治疗药物。
